Questions engineers ask

Checking the local stress where something is welded to a pressure vessel: nozzles and clips by WRC 537 and by a finite-element shell model, lifting and tailing lugs, agitator nozzles, skirt openings and API 661 air-cooler headers to ASME VIII-1 Appendix 13.

The WRC 537 calculator is complete and shows every coefficient and code paragraph. The finite-element modules are in early access for invited engineers and are under independent verification; until that is finished their results are not a source of design values.

WRC Bulletin 537, ASME VIII-1 (UG-27 and Appendix 13), ASME VIII-2 Part 5 (stress categories, 5.2.3 limit-load, 5.4.2 buckling, 4.5.17.3), Moss procedures 10-3 to 10-8, and ASME BTH-1 and B30.26 for lifting lugs.

No. Shell thickness and opening reinforcement for pressure are sized in your vessel program. FEXLA checks what is attached to the shell and the loads it brings.

On a cylinder: a round nozzle, radial or hillside, or a rectangular clip. On a cone: a round nozzle. On a formed head: a round nozzle in the spherical region. A reinforcing pad is optional on each.

Yes. Rectangular clips and the brackets that carry platforms, supports and ladders are checked with the clip calculator, by WRC 537. Structural sections and clips close to a seam or another attachment go to the finite-element shell model.

Yes. It steps the lift through its angles, finds the load at each lug, checks the plate to Moss and AISC and to BTH-1, checks the shackle fit and the shell under each lug by WRC 537. Trunnions, a tail beam and two offset lugs are covered; a base ring is checked by hand. A shell model of the governing lug is one of the finite-element tools.

Yes. A nozzle on a top head carrying an agitator, under its weight, thrust, torque and rotating bending moment, with the fatigue cycles worked out from speed, running hours and the number of starts.

Yes, plug headers and welded rectangular boxes to ASME VIII-1 Appendix 13: the stress at each location, the tube-hole ligaments, end plates and stays, the required thickness, the MAWP and the test condition. Nozzle and support loads on the header are not covered; check a header nozzle as an attachment.

Yes. A tombstone, obround or round access opening in a support skirt, with its sleeve and an optional pad, under weight and wind or seismic moment, with the ASME VIII-2 4.5.17.3 hand checks beside the shell model. The base ring, gussets and anchor chairs are not modelled.

All six components of the bulletin: a radial load, two shear forces, two bending moments and a torsional moment. You can give them at the shell junction or at the end of the nozzle, and the calculator carries them to the junction. Pressure is added to the local stresses.

When the bulletin stops: a case outside its charted range, an attachment close to a head, a cone junction, a seam or another attachment, a large opening for the shell, a tilted or tangential nozzle, an obround opening, or stresses wanted in the nozzle or the pad. The calculator tells you when a case falls outside the bulletin and offers to carry it across.

Several attachments and load cases on one vessel, run together or one by one with a pass/fail grid (a CSV schedule in and out); a solid (brick) model of a junction or of the whole modelled vessel, fillet welds included, with stress classification lines through the wall (VIII-2 Annex 5-A); vessels on legs; eigenvalue buckling to VIII-2 5.4.2 and an elastic-perfectly plastic limit-load check to 5.2.3. Large-displacement analysis, local strain limits and elastic-plastic ratcheting are not done yet.

Any material you name. You type the allowable stress S at your design temperature from your own copy of ASME Section II Part D, and the edition you read it from; the report prints both as entered. The calculator has no built-in material list and does not check S. Metric and U.S. units both work, and you can switch between them.

The stresses at every evaluation point, the pass or fail against 1.5S and 3S, a 3D model of the case and a calculation report. You can save the case to your history and download the report as a PDF.

The WRC 537 calculator and the lifting and tailing lug calculator (the lift, the lug, its weld and the shell under it by WRC 537) are free during early access, and every new account is reviewed before it is opened. The finite-element tools, the lug and leg shell models among them, are not free: they are priced separately and open to invited engineers, so ask us about access.